Good question, Craig. I stumbled upon this
article from a Memphis newspaper written while the search for Earhart and Noonan was proceeding. The article provides a glimpse into the thinking behind searching north (and south) of Howland, the split opinions and confusion as to where to search, who held those opinions, and why. The article is difficult to read from the linked photo, so I transcribed it (attached). This is a debate that continues here and elsewhere to this day and on much of the same evidence. (This subject is also explored in depth in
Finding Amelia.)
The remarkable thing about the article is that it shows the Nikumaroro hypothesis is not new. Nikumaroro was in fact one of the earliest of candidates on where to search, and based on good evidence from people familiar with the specifications of the Electra, the navigational practices of Fred Noonan, and radio direction finding of the time. The idea of searching northward had its adherents, too, who based their beliefs on the contents of a radio message that stated, cryptically, "281 North Howland."
It seems to have been a good idea to chase down both leads to the north and the south, as was done. So the question basically becomes - if you were reading the Memphis Press-Scimitar in July of 1937, knowing only what they knew then, where would you think would be the most likely place to look?
Joe Cerniglia
TIGHAR #3078ER